Cosmic ray interactions in meteorites     

Ludolf Schultz 《Meteoritics & planetary science》1992,27(4):325-325

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On the electrical conductivity of the mid-mantle-I. Calculation of equivalent scalar magnetotelluric response functions   总被引：2，自引：0，他引：2  

A. Schultz  J. C. Larsen 《Geophysical Journal International》1987,88(3):733-761

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Oscillatory motions in sunspots     

J. M. Beckers  R. B. Schultz 《Solar physics》1972,27(1):61-70

We observe vertical velocity oscillations in some sunspot umbrae with periods of about 180 s and peak to peak amplitudes up to 1 km s^–1. These oscillations are not visible in either the line depth, line width or the continuum intensity. No correlation seems to exist between the occurence of these oscillations and the presence of the chromospheric umbral flashes (Solar Phys. 7, 351, 1069). In the spot penumbra there is an indication of a long period oscillation, the period increasing from about 300 s in the inner penumbra to nearly 1000 s at the penumbra-photosphere boundary. An attempt has been made to interpret these oscillations in terms of gravity or acoustic waves, travelling along the magnetic field lines, taking into account the variation of scale height and magnetic field direction across the sunspot.  相似文献   

Global and regional ridge patterns on Mars   总被引：1，自引：0，他引：1  

Agustin F. Chicarro  Peter H. Schultz  Philippe Masson 《Icarus》1985,63(1):153-174

Over 16,000 wrinkle ridges on Mars have been classified, mapped, and digitized to provide a large computer-accessible data base for analyzing regions subjected to possible compressive stresses. The survey has revealed major compressive structures that occur well beyond the Tharsis-dominated hemisphere. The large variety of affected geologic terrains indicate stresses not simply localized in the intercrater plains. One major area of inferred compression occurs in the southern cratered highlands near longitude 180°W where major ridges and scarps extend over 3000 km. The occurrence and orientation of many ridges are locally controlled by ancient impact basins. The Chryse basin in particular has an important effect on ridges in northern Lunae Planum. The removal of all basin-concentric ridges reveals, however, a complex global pattern. Although such patterns may yet be controlled by heavily degraded impact basins, major regional trends also emerge that appear to require broader scale global stresses. Most ridges in the Western Hemisphere are shown to be orthogonal to three centers corresponding to Tharsis (1°N, 122°W), Syria (12°S, 104°W), and Chryse (19°N, 47°W). Ridges not included in these three sets are generally more random and highly localized. Most, but by no means all, ridges in the Eastern Hemisphere are controlled by the Hellas and Isidis basins. A simple global grid is not yet identifiable and may not be recognizable owing to the large number of regional patterns.  相似文献   

Eemian landscape response to climatic shifts and evidence for northerly Neanderthal occupation at a palaeolake margin in northern Germany     

Michael Hein  Brigitte Urban  David Colin Tanner  Anton Hermann Buness  Mario Tucci  Philipp Hoelzmann  Sabine Dietel  Marie Kaniecki  Jonathan Schultz  Thomas Kasper  Hans von Suchodoletz  Antje Schwalb  Marcel Weiss  Tobias Lauer 《地球表面变化过程与地形》2021,46(14):2884-2901

The prevailing view suggests that the Eemian interglacial on the European Plain was characterized by largely negligible geomorphic activity beyond the coastal areas. However, systematic geomorphological studies are sparse. Here we present a detailed reconstruction of Eemian to Early Weichselian landscape evolution in the vicinity of a small fingerlake on the northern margin of the Salzwedel Palaeolake in Lower Saxony (Germany). We apply a combination of seismics, sediment coring, pollen analysis and luminescence dating on a complex sequence of colluvial, paludal and lacustrine sediments. Results suggest two pronounced phases of geomorphic activity, directly before the onset and at the end of the Eemian period, with an intermediate period of pronounced landscape stability. The dynamic phases were largely driven by incomplete vegetation cover, but likely accentuated by fluvial incision in the neighbouring Elbe Valley. Furthermore, we discovered Neanderthal occupation at the lakeshore during Eemian pollen zone (PZ) E IV, which is chronologically in line with other known Eemian sites of central Europe. Our highly-resolved spatio-temporal data substantially contribute to the understanding of climate-induced geomorphic processes throughout and directly after the last interglacial period. It helps unraveling the landscape dynamics between the coastal areas to the north and the loess belt to the south.  相似文献   

Scouring the surface: Ejecta dynamics and the LCROSS impact event     

Brendan Hermalyn  Peter H. Schultz  Mark Shirley  Kimberly Ennico  Anthony Colaprete 《Icarus》2012,218(1):654-665

The Lunar CRater Observation and Sensing Satellite mission (LCROSS) impacted the moon in a permanently shadowed region of Cabeus crater on October 9th 2009, excavating material rich in water ice and volatiles. The thermal and spatial evolution of LCROSS ejecta is essential to interpretation of regolith properties and sources of released volatiles. The unique conditions of the impact, however, made analysis of the data based on canonical ejecta models impossible. Here we present the results of a series of impact experiments performed at the NASA Ames Vertical Gun Range designed to explore the LCROSS event using both high-speed cameras and LCROSS flight backup instruments. The LCROSS impact created a two-component ejecta plume: the usual inverted lampshade “low-angle” curtain, and a high speed, high-angle component. These separate components excavated to different depths in the regolith. Extrapolations from experiments match the visible data and the light curves in the spectrometers. The hollow geometry of the Centaur led to the formation of the high-angle plume, as was evident in the LCROSS visible and infrared measurements of the ejecta. Subsequent ballistic return of the sunlight-warmed ejecta curtain could scour the surface out to many crater radii, possibly liberating loosely bonded surface volatiles (e.g., H₂). Thermal imaging reveals a complex, heterogeneous distribution of heated material after crater formation that is present but unresolved in LCROSS data. This material could potentially serve as an additional source of energy for volatile release.  相似文献   

First record of stereospondyls (Tetrapoda,Temnospondyli) in the Upper Triassic of Southern Brazil     

Sérgio Dias-da-Silva  Eliseu Vieira Dias  Cesar Leandro Schultz 《Gondwana Research》2009,15(1):131-136

Stereospondyls survived the Permo-Triassic extinctions in a refuge probably located in the landmass that nowadays comprises Australia. Subsequently, they radiated to other parts of Pangaea, reaching their highest distribution and diversification during the Early Triassic. An incomplete interclavicle from the Caturrita Formation represents their first record in the Upper Triassic of Brazil. Previously, Upper Triassic South American stereospondyls were restricted to Argentina. This new record reinforces a former hypothesis that suggests the presence of a more diverse stereospondyl fauna in South America during the Late Triassic than previously assumed. Additionally, the presence of a stereospondyl and a phytosaur in the Caturrita Formation reinforces the hypothesis of a change to more humid climatic conditions in the Paraná Basin during the Upper Triassic. The record of Early Triassic stereospondyls in South America suggests that they first colonized Brazil and/or Uruguay, spreading from South Africa during the Early Triassic, subsequently reaching Argentina. Up till now, there is no record of Middle Triassic stereospondyls in either Argentina and Brazil, probably due to either taphonomic bias or insufficient prospecting. Despite the lack of direct evidence, one should not dismiss an earlier stereospondyl colonization of Argentina still during the Early or Middle Triassic.  相似文献   

Tracking cohorts: Analysis of migration in the early life stages of an estuarine fish     

Eric T. Schultz  John Young  Jennifer M. Martin  Kamazima M. M. Lwiza 《Estuaries and Coasts》2005,28(3):394-405

Larvae and juveniles are often most abundant at some distance from where spawning occurs. Such apparent distribution shifts can be the result of larval migration, seasonal shifts in the distribution of spawners, or spatial heterogeneity in mortality. In the present study, a cohort-based method was adopted to test for larval migration of bay anchovy (Anchoa mitchilli) and to estimate its rate and timing. A spatially and temporally extensive series of ichthyoplankton samples was collected in the lowest 122 km of the Hudson River in summer 1998. Bay anchovy eggs and young-of-year individuals were abundant (mean density=1.6 m^?3 and 0.95 m^?3, respectively). Daily age used to define cohort membership was determined from otoliths. Age and length were strongly related (R²=0.74). The age-length relationship varied over the season such that early-season bay anchovy hatched in June grew more rapidly than later-season anchovy hatched in August. Cohorts were defined as week-long birth-data classes, and net migration patterns of 11 cohorts were analyzed. Mean location shifted upriver as cohorts increased in age to 6 wk, at a net rate of about 0.6 km d^?1. Cohort abundance usually decreased over time in downriver regions, but usually increased in upriver regions. The cohort analysis confirmed that the upriver shift in distribution of early-stage anchovy is not entirely due to changes in adult spawning behavior or to clines in larval mortality, and must be partly the result of larval migration.  相似文献   

Tornado outbreaks associated with landfalling hurricanes in the North Atlantic Basin: 1954–2004     

S. M. Verbout  D. M. Schultz  L. M. Leslie  H. E. Brooks  D. J. Karoly  K. L. Elmore 《Meteorology and Atmospheric Physics》2007,97(1-4):255-271

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Enhanced Backscattering of Seismic Waves From A Highly Irregular, Random Interface: Sh Case     

Craig A. Schultz  M. Nafi Toksöz 《Geophysical Journal International》1993,114(1):91-102

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